get_promo_rule

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true. Description adds that it returns 404 for invalid store_id or promo_rule_id, and lists returned fields, which provides context beyond annotations. Rate limits or auth are not mentioned but are acceptable for a simple read operation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Description is well-structured: purpose sentence, usage guidance, error behavior, args list, return list. No wasted words, each sentence adds value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's simplicity, the description covers all essential aspects: purpose, when to use, alternatives, error conditions, parameters, and return values. No gaps given that an output schema exists and annotations are present.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so description must explain parameters. It explains store_id and promo_rule_id briefly but omits the optional account parameter entirely. The returned fields list helps but doesn't cover all params.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool retrieves a single promo rule by ID with full configuration, using a specific verb and resource. It distinguishes from siblings like list_promo_rules for browsing IDs.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly says when to use: inspect before updating or confirm existence before attaching codes. Provides alternative: use list_promo_rules to discover IDs. Also notes 404 for invalid IDs.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.